I am not a 400 series expert (though I got fairly familiar with several 300 types). However, be
very careful about the structural AD's which might be applicable. Some are very expensive to comply with. In one case one of my client maintenance shops disassembled the wing of a 4XX (don't remember which model exactly), to find that the corrosion was not bad, but Cessna had misdrilled some fastener holes, and it was major work to correct that mistake.
Become very familiar with what you're looking at before you put money down!
If you're new to multi engine aircraft, I highly recommend considering what is written in this article:
http://www.avhf.com/html/Library/Lea...elf_An_Out.pdf